Pure water, which has been obtained by removing impurities from water, has a feature of causing no adverse effects by the impurities. Therefore, it has been widely used in cleaning various kinds of devices such as a semiconductor, or manufacturing chemical substance such as pharmaceutical preparations, etc., in addition to use of test or experiment. However, such pure water has characteristics and properties that allow a relatively high level of dissolution of other substances into the water, compared to ordinary or non-purified water. It has recently been used also for drinking or edible use by adding naturally-derived nutritional components or flavor components thereto.
Various kinds of methods such as a filtration method, an ion-exchange method, a method utilizing a reverse osmosis membrane, etc. are used for manufacture of pure water. However, a manufacturing method utilizing distillation has conventionally being used widely as an easy and effective method. A pure water manufacturing apparatus utilizing such a distillation process is disclosed for example in JP 06-63535 A, JP 2006-167535 A or JP 2002-79237 A.